1. Field of the Invention
The present invention relates to a venting device for use in a hollow structure such as a refrigerator door to be filled with foamed-in-place insulation.
2. Brief Description of the Prior Art
Insulated structures, such as refrigerators, freezers or the like incorporate insulation within their outer walls to prevent the exchange of heat between the internal enclosed compartment and the outside environment. In the past, it was the practice to provide the insulation by hand within the outer walls of the insulated structure. One problem associated with such manual application of insulation was that the process was time consuming and would result in a nonuniform distribution of insulation, producing a less efficient device.
Foamed-in-place insulation was developed to alleviate inadequacies in insulation application procedures. The foamed-in-place insulation is generated from a foamable liquid resin, such as a foamable polyurethane resin. The liquid resin is introduced within the outer walls of hollow structure to be insulated, and caused to foam. The foam is typically generated chemically or by use of a gaseous foaming or "blowing" agent.
It has been the practice in the art to provide the outer walls with holes, which are temporarily covered with either fiberglass or porous tape, to allow gases to escape while the foamable resin expands to fill the outer walls. The fiberglass or porous tape, however, does not adequately prevent the escape of foam. Usually, the fiberglass or porous tape is applied on the interior of the structure so that the tape cannot be removed after the foam has been installed. However, the tape must be later perforated and the apertures plugged. It is desirable to eliminate the escape of foam into the environment, and to eliminate the handling of fiberglass by employees.
One approach to solving this problem is disclosed in U.S. Pat. No. 4,955,675, which provides a venting device having small, round apertures formed in an end wall. The apertures permit gas from expanding insulation material to escape. However, the apertures are sized to retard passage of the semi-solid polymeric foam. In addition, the venting device may only be mounted adjacent a corner. The configuration of an insulated structure may be such that it would be necessary to provide a venting device in areas of an insulated structure other than, or in addition to the corners, in order to insure that all the gases will escape so that the foamed-in-place insulation may fill the structure.